Answer:
5.0 %
Explanation:
Given data
- Volume of ethylene glycol (solute): 50 mL
- Volume of water (solvent): 950 mL
Step 1: Calculate the volume of solution
If we assume that <em>the volumes are additive</em>, the volume of the solution is equal to the sum of the volume of the solute and the solvent.
V = 50 mL + 950 mL = 1000 mL
Step 2: Calculate the percent by volume
We will use the following expression.
Answer:
(2) The lowest energy orbits are those closest to the nucleus.
Explanation:
In the Bohr theory the electrons describe circular orbits around the nucleus of the atom without radiating energy, therefore to maintain the circular orbit, the force that the electron experiences, that is, the coulombian force due to the presence of the nucleus, must be equal to the centripetal force.
The electron only emits or absorbs energy in the jumps from one allowed orbit to another, with only one jump occurring at a time, from layer K (n = 1) to layer L (n = 2), without going through intermediate orbits. In said change it emits or absorbs a photon whose energy is the difference in energy between both levels.
In Bohr's model, it is stipulated that the energy of the electron is greater the greater the radius r, so the lowest energy orbits are those closest to the nucleus.
Answer:
a. 108.19 amu
Explanation:
Isotopes are atoms of the same element, which have the same number of protons and electrons, but a different number of neutrons, and, because of that, different masses.
The atomic mass (M) in the periodic table is a ponderation of the masses of all isotopes found in nature. Thus, it is the summation of the percent multiplied by the mass of each isotope, so:
M = 0.5184*106.90509 + 0.4846*108.90476
M = 108.19 amu
amu = atomic mass unit.
